Power-actuated banding tool



May 21, 1963 B. B. WEISS ETAL POWER-ACTUATED BANDING TOOL 2 Sheets-Sheet 1 Filed July 18, 1961 INVENTORS.

4 BEPNNAQDT B. h /Ss CcnyroN D. RUNNING May 21, 1963 B. B. WEISS ETAL POWER-ACTUATED BANDING TOOL 2 Sheets-Sheet 2 Filed July 18, 1961 a g S 556 WW w W R Z 1 Z @W WW 4 3 Be 3,090,599 POWER-ACTUATED BANDING TOOL Bernhardt B. Weiss, Los Angeles, and Clayton 1). Running, Manhattan Beach, Calif., assignors to Paris Precision Products, a partnership Filed July 18, 1961, Ser. No. 124,925 9 Claims. (Cl. 254-51) This invention related generally to a banding tool and more specifically in its preferred form discloses a poweractuated tool for tightening a banding strap around a transformer core made up of a plurality of laminations, although it will be evident that the tool has other applications as well.

In many industrial applications, such as banding of transformer cores, it is important that the banding strap be applied around the core with a predetermined tension, and that such tension be maintained constant throughout the banding of a number of cores in a production run. Moreover, it is important for flexibility of operation that the tension be selectively adjustable by the operator in order to accommodate the banding tool to different models of types of transformer cores or other work pieces being banded.

In the preferred embodiment of the present invention hereinafter illustrated and described, there is provided a power means including an air-actuated piston within a cylinder, the pressure of air admitted to the cylinder being selectively controllable by the operator. The piston is provided with a piston rod projecting outwardly of the cylinder and operatively connected to a piston rod extension which is axially slidable in guide means formed in an elongated housing formed in a support frame on which the cylinder is mounted. The piston within the cylinder is resiliently rearwardly biased into retracted position. Admission of air into the cylinder forces the piston forwardly into extended position against the resistance of the biasing means and the piston is restored to retracted position when the air pressure is released from the cylinder.

It will thus be seen that the piston rod extension is caused to reciprocate longitudinally during operation and means are provided for rectifying such reciprocating motion and thus converting it to uni-directional incremental longitudinal movement of a ram member in the forward direction. Such means include a dog pivotally carried on the piston rod extension and engageable with serrations formed upon the slidably mounted elongated ram. Selectively disengageable ratchet means carried by the housing and engageable with the ram serve to maintain the ram in partially extended position as it is moved forward of the piston rod extension. Means are provided on the housing for selectively locking the banding strap used in the banding operation. The banding strap extends from the locking means to the outer end of the ram where the strap passes through a slotted guide member carried on the outer end of the ram and continues through a keeper or banding seal to extend around the transformer core or other workpiece being banded. Thus forward or extended movement of the ram causes the banding strap to be cinched around the core to a tightness determined by the air pressure actuating the piston rod extension. Thereafter the banding strap is soldered in position to maintain the core under proper compression. In operation, the air pressure is then relieved from the actuating cylinder, the ram is released from the ratchet engagement maintaining it in extended position, and the banded core is withdrawn slightly from the outer end of the ram to permit the strap to be cut to desired length. The machine is then ready for another banding operation on the same or a different core. It will be noted that the maximum stroke of the power were Patented May 21, 19%3 actuated piston rod and extension can be substantially less than the maximum stroke of the ram, thus minimizing the necessary sizes of the components for a given ram stroke.

Accordingly, it is a principal object of the present invention to provide a novel power-actuated banding machine for tightening a banding strap With predetermined tension about a workpiece to be banded. Other objects are to provide such a machine wherein successive reciprocating, relatively short stroke movements of an actuating member are converted into progressive uni-directional movements of a force-applying member having a substantially greater maximum stroke; to disclose such a machine designed to facilitate rapid, accurate banding at a desired tension of the banding strap used; and for other and additional purposes as will be understood from a study of the following description of a preferred embodiment of the invention taken in connection with the accompanying drawings in which:

FIG. 1 is a top plan view of the banding machine in accordance with the present invention, with the air pressure regulator and pressure-indicating gage shown in diagrammatic relation to the machine, the ram being shown in retracted position.

FIG. 2 is a view, partially in section, taken along the line *IIII of FIG. 1, including a transformer core to be banded and the banding strap initially looped therearound.

FIG. 3 is a side elevational view of the machine, parts being shown in section, with the piston rod extension and the ram being shown in their extended operative positions during banding; a soldering iron is fragmentarily shown in position to solder the banding seal or keeper in pos1tion.

FIGS. 4, 5 and 6 are sectional views taken on lines IV-IV, V-V and VI-VI, respectively, of FIG. 3.

FIG. 7 is a perspective view of one form of a clip or keeper used as a banding seal in accordance with the invention.

FIG. '8 is a fragmentary View on an enlarged scale of the upper left portion of the transformer core and banding parts after the banding strap has been initially hand-tightened around the core and before power is applied to complete the banding process.

Referring now in detail to the drawings and first to FIGS. 1 and 3 thereof, the banding tool or machine of the present invention is carried on a base indicated generally at 10 and desirably in the form of a U-shaped member having a pair of spaced arms 11 and 12 fixed by conventional means 13 to a supporting surface or work table 14. The base plate 10 may be provided with an enlarged boss indicated generally at 16 provided with a bore constituting a socket for receiving the lower end of an upright support rod 17, the lower end of the rod being held in the socket by conventional retaining means 18. In the upper portion of the support rod 17 there is carried a horizontally disposed mounting plate indicated generally at 20 and having a bore near a bifurcated end for receiving the rod 17. The bifurcated arms 21 permit the mounting plate to be clamped on the rod by means of clamping means 22.

The mounting plate 20 extends generally transversely of the machine and a frame member indicated generally at 2 4 is fixed to the plate by suitable means 25. The frame member 24 includes an enlarged flange portion 26 and a forwardly projecting elongated housing indicated generally at 28.

A cup-shaped cylinder indicated generally at 30 is fixed to the frame 24 by suitable fastening elements 31 threaded into the side wall of the cylinder 30. The member 30 is provided with an internal cylindrical bore 32 in which is slidably mounted a piston indicated generally at 34 carried on a piston rod 36 passing through a bore 38 formed in the frame member 24. The piston 34 is biased leftwardly as seen in FIGS. '2 and 3 by resilient means desirably in the form of a coiled spring 40, an end portion of the spring being received in an an nular recess formed in the frame member 24.

The base 44 of the cup member 30 is centrally ported at 46 for inlet of air under pressure from a conduit or tube 48. The other end of the tube 48 is connected to an air valve indicated generally at 50 and provided with a depress-ible operating handle indicated generally at 52. Desirably the valve 50 is of the type which may be locked in open position, as by a partial rotation of the handle 52. The -valve 50 in turn is supplied'with air under pressure through the conduit 54 which leads from a pressure regulator indicated generally at 56 of well-known construction having an adjusting knob 58 and provided with a pressure gage 60 indicating the pressure within the conduit 54. The pressure regulator 56 is supplied with air through conduit 62 connected to a suitable source of pressurized air. It will thus be seen that the pneumatic components just described permit air under the pressure selected by the operator by means of knob 58 to be fed under the control of valve 50 into the cylinder of cup member 30. Such admission of pressurized air into the cylinder 30 causes the piston 34 and its associated piston rod 38 to be moved rightwardly from their retracted positions seen in FIG. 2 to their extended positions seen in FIG. 3.

A piston rod extension indicated generally at 70 is longitudinally slidably mounted in the housing 28 and is connected in axial prolongation of rod 38 by suitable means such as the pin 72 received in an opening formed in the piston rod extension. Intermediate the ends of extension 70 there is pivotally carried a latch member or dog indicated generally at 74 pivotable about the axis of pin '76 between an upper inoperative position seen in FIG. 2 and a lower operative position seen in FIG. 3.

' Resilient means may be provided for urging the dog into its operative position of FIG. 3, such means being here shown as including an elongated leaf spring 78 received in a recess 80 formed in the housing 28 above the guideway in which piston rod extension 70 is slidably mounted. Spring 78 serves to urge downwardly the upper finger 82 of the dog 74, so that the lowermost extent or blade 84 of the dog is urged downwardly into its FIG. 3 position.

Also slidably mounted within the housing 28 and desirably in substantially parallel relation with the piston rod 70 is 'an elongated arm or ram indicated generally at 90 and desirably of rectangular cross-section. Extending over a substantial portion of its upper surface is a series of transverse teeth or serrations indicated generally at 2, the blade 84 of dog 74 being engageable in ratchet manner with a selected one of the serrations. Means are provided on the ram 90 for retaining the rain in partially or fully extended position as it may be driven by the piston rod extension through the ratchet engagement of dog 74. In the present illustrative embodiment of the invention, such means include a second set of teeth or serrations indicated generally at formed on a side Wall of the ram '90 selectively engageable by a manually releasable looking member or pawl indicated generally at 102 and mounted in the housing closure plate indicated generally at 104. The latter plate is retained in assembled relation with the housing 28 by cap screws, one of which is seen-at 106 in FIG. 4, engageable in threaded bores 108 in the body portion of the housing. The plate 104 includes an enlarged boss 110 having an internal recess 112 wherein is pivotally mounted the pawl 102 about the axis of pivot pin 114. Pawl 102 is biased into locking position as seen in FIG. 5 by a resilient element 116.carn'ed within the boss 100. Pawl 102 is also provided with an elongated arm 118 extending outwardly of the boss 110, the arm being digital-1y movable upwardly as seen in FIG. 5 in order to release the latching engagement of the opposite end 120 of the pawl from the serrations 100 on the ram.

Means are desirably provided on the ram for limiting.

extended or forward movement thereof, such means here taking the form of an outwardly projecting pin (see FIG. 4) slidably received in a longitudinal groove 124 formed in the inner wall of the closure plate 104, the groove 124 terminating forwardly in a shoulder 126 against which pin 122 abuts to limit forward movement of the ram 90.

The sequence of operation of the present banding machine will now be described in connection with the :banding of a transformer core indicated generally 'at 130 and including a base portion 132 and a cap portion 134. Around one leg of core 130 is a coil' indicated generally at 136 and provided with conventional leads 138 adapted to be connected to external circuitry as may be desired. The banding strap indicated generally at 140 includes a portion 141 extending upwardly from a supply source of strap (not shown) through a manually actuated locking device indicated generally at 142. From the lock 142 the banding strap extends rightwardly as seen in FIG. 2 through a slotted guide member indicated generally at 144 and carried on the outer end of the ram 90. Within the guide 144 (see FIG. 8 there extends a slot 146 of restricted size slidably receiving the banding strap 140. The strap then continues through a keeper or band seal indicated generally at 150, the seal (see FIG. 7) being desirably in the form of a U-shaped metallic member having inturned upper portions 151 and 152 partially overlying the strap extending therethrough. From the seal 150, with further reference to FIG. 2, the strap continues in a clockwise direction around the core 130, passing through the coil 136, and again passing through the seal 150. The terminal portion of the strap is bent backward at 152 after passing through the seal the second time, and the terminal portion 154 extends partially around the core 130 in a counter-clockportion pivotally supported by the boss 110 around the axis of pivot pin 162 and a handle member 164 projects outwardly for convenient grasp by the operator. Desirably, the outer surface of the enlarged eccentric portion 160 is knurled or otherwise roughened as best seen in 'FIG. 4 so that, with the locking handle 164 moved into its upper position as seen in FIG. 3, the eccentric member 160* wedgingly locks the strap against the inner opposed surface 166 of the boss.

With the parts in this position, the control valve handle 52 is depressed, resulting in rightward movement of the piston rod extension 70, which movement is transmitted to the ram 90. When air pressure is now released, the latter element will be maintained in its partially projected position by the locking engagement of pawl 102, while the piston and piston rod extension are retracted to their positions seen in FIG. 2 under the force of spring 40. Successive depressions of valve handle 52 cause the piston rod extension to again force the ram 90 outwardly or forwardly incrementally until no fur-ther movement occurs and the parts assume their positions seen in FIG. 3. At that point, the seal is soldered to the strap as indicated by the soldering iron fragmentarily shown and indicated generally at 170, and the'ram may then be permitted to return toits retracted position by the operators actuation of the pawl handle 118, the piston rod extension having meanwhile been retracted by the spring 40 when air pressure is removed from the cylinder 30. It is to be noted that, when t e piston rod extension is retracted, the dog 74 is swung upwardly into inoperative position by abutting engagement with a pin 172 carried by the housing 28 and extending transversely thereof. With the ram retracted, the operator can cut the strap at a desired point near the seal 150, thereby releasing the banded core and preparing the machine for a subsequent banding operation. The lock 142 is disengaged by rotating the handle 164 downwardly to permit an additional length of strap to be pulled through the blade 144.

Accordingly, it will be seen that the machine in accordance with the present invention imposes upon the banding strap a predetermined tension under the control of the operator by means of the adjusting knob 58 on the regulator. -It is to be particularly noted that the length of stroke of the piston rod 36 and the piston rod extension 70 is relatively short, thus permitting a compact arrangement of the parts, while the maximum longitudinal or stroke movement of the ram 90 may be many times that of the piston rod extension.

Although the invention has been described in connection with the banding of transformer cores, and has particular advantages in connection with such operation because of the close and accurate control of the banding tension, nevertheless it will be understood that principles of this invention are applicable also in other banding operations. Modifications and changes from the specific illustrative embodiment of the invention herein shown and described will occur to those skilled in the art, and all such modifications and changes not departing from the spirit of the invention are intended to be embraced within the scope of the appended claims.

We claim:

1. A banding machine comprising: a frame including an elongated forwardly directed housing; an elongated ram slidably mounted in the housing and projectable forwardly therefrom; selectively disengageable means carried by the housing for preventing rearward movement of said ram; banding strap guide means carried on the forward portion of the ram forming a restricted passageway for slidably receiving banding strap; means for selectively locking banding strap against movement relative to the housing; and selectively operable power means for impressing on said ram a forwardly directed force of predetermined strength, including a member movably carried by the frame for reciprocating longitudinal movement generally parallel to the axis of ram movement.

2. The invention as stated in claim 1 including means carried by said member and engageable with the ram for transmitting forward movement of the member to the ram.

3. The invention as stated in claim 1 wherein maximum longitudinal movement of said member is substantially less than maximum longitudinal movement of the ram.

4. A banding machine comprising: a frame including an elongated forwardly directed housing; an elongated ram slidably mounted in the housing and projectable forwardly therefrom; banding strap guide means carried on the forward portion of the ram; means for selectively locking banding strap against movement relative to the housing; and selectively operable power means for impressing on said ram a forwardly directed force of predetermined strength, including a member movably carried by the frame for reciprocating longitudinal movement generally parallel to the axis of ram movement.

5. An invention as stated in claim 4 including selectively disengageable means carried by the housing for preventing rearward movement of the ram.

6. The invention as stated in claim 5 wherein the movement of said member is substantially shorter than maximum ram movement, and resilient means for biasing said member rearwardly.

7. The invention as stated in claim 6 including means carried by the member and engageable with the ram for transmitting forward member movement to the ram, and means for disengaging said engageable means when the member is in its rearmost position.

8. In a banding machine, in combination: a support frame; a banding strap guide member mounted for reciprocating longitudinal movement relative to the frame, the guide member including slot means closely, slidably receiving a banding strap extending therethrough; selectively operable means carried by the frame for incrementally urging said guide member forwardly under force of preselected value, including an elongated member mounted for reciprocating longitudinal movement generally parallel to the axis of guide member movement; and means for selectively locking a portion of banding strap relative to said frame.

9. The invention as stated in claim 8 including power means for forcing said elongated member forwardly and resilient means biasing the elongated member rearwardly, the maximum stroke of the elongated member being substantially less than that of the guide member.

References Cited in the file of this patent UNITED STATES PATENTS 1,319,126 Turner Oct. 21, 1919 2,281,438 Heslet et al Apr. 28, 1942 2,893,689 Hepler July 7, 1959 

4. A BANDING MACHINE COMPRISING: A FRAME INCLUDING AN ELONGATED FORWARDLY DIRECTED HOUSING; AN ELONGATED RAM SLIDABLY MOUNTED IN THE HOUSING AND PROJECTABLE FORWARDLY THEREFROM; BANDING STRAP GUIDE MEANS CARRIED ON THE FORWARD PORTION OF THE RAM; MEANS FOR SELECTIVELY LOCKING BANDING STRAP AGAINST MOVEMENT RELATIVE TO THE HOUSING; AND SELECTIVELY OPERABLE POWER MEANS FOR IMPRESSING ON SAID RAM A FORWARDLY DIRECTED FORCE OF PREDETERMINED STRENGTH, INCLUDING A MEMBER MOVABLY CARRIED BY THE FRAME FOR RECIPROCATING LONGITUDINAL MOVEMENT GENERALLY PARALLEL TO THE AXIS OF RAM MOVEMENT. 